1. Field of the Invention
The present invention is generally drawn to single crystal components, and particularly to single crystal sheets, methods for forming such sheets, and processing equipment used in connection with the formation of single crystal sheets.
2. Description of the Related Art
Single crystals such as sapphire have been a material of choice for demanding, high performance optical applications, including various military and commercial applications. Single crystal sapphire possesses good optical performance within the 200 to 5000 nanometer range, and additionally possesses desirable mechanical characteristics, such as extreme hardness, strength, erosion resistance, and chemical stability in harsh environments.
While certain demanding high performance applications have taken advantage of single crystal sapphire, its implementation has not been widespread partly due to cost and size limitations due to forming technologies. In this regard, single crystal sapphire in the form of sheets is one geometric configuration that holds much industrial promise. However, scaling size while controlling processing costs has been a challenge in the industry. For example, processing equipment has not been adequately developed for the repeatable production of large-sized sheets, and additionally, processing techniques have not been developed for reliable manufacture.
A publication entitled “Large Diameter Sapphire Window from Single Crystal Sheets” from the Proceedings of the Fifth DOD Electromagnetic Window Symposium, Volume I (October 1993) provides a description of sapphire sheet processing (co-authored by the present inventor). However, the technology described in the paper is confined, particularly limited to moderate sheet sizes.
In light of the foregoing, the industry continues to demand large-sized single crystal sheets that can be produced in a cost-effective manner, such that improved size and reduced cost enable the implementation of sheets in various applications that, to date, have not been exploited. In addition, there is a particular demand for large-sized sapphire sheets.